Glaucoma causes irreversible blindness if left untreated. Sixty (60) million people were diagnosed with glaucoma in 2010, eight (8) million of whom progressed to blindness. Glaucoma occurs when the intraocular pressure (IOP) in the eye increases above normal levels due to a higher inflow of aqueous fluid than outflow. While drug therapy is effective, compliance is a problem as drug therapy usually entails multi-drug regimens. For example, a study has shown that for patients undergoing drug therapy there is 50% non-compliance at 6 months of drug therapy. Trabeculectomy, which is invasive, is typically used when drug therapy fails. While trabeculectomy can be effective, it has been shown to have a 46.9% failure rate at 5 years after surgery primarily due to the formation of scar tissues.
Glaucoma drainage devices (hereinafter ‘GDDs’) can be used for patients refractory to drug treatment and patients who have undergone a failed trabeculectomy. There is now mounting evidence that GDDs, typically used only in the most refractory of cases, are as safe and effective as trabeculectomy in IOP control. In some cases, GDDs have been found to be more effective than trabeculectomy in IOP control.
GDDs, also known as glaucoma filtering devices or aqueous shunts, are surgical implants that permit the drainage of intraocular fluid from the interior of the eye to the exterior of the eye thereby lowering intraocular pressure. GDDs have been in use since the early 1970s and two standard designs persist. To date, no significant advances in the design of GDDs have been made.
The challenge is in improving the design of GDDs to eliminate the problems associated with presently available GDDs. For example, with respect to presently available GDDs, at 5 years after surgical implantation a conventional Baerveldt device has shown a 36% failure rate, and a conventional Ahmed device has shown a 44% failure rate. Such failure rates are due to occluded flow, inflammation, and fibrous encapsulation associated with the presently available GDDs.
Therefore, there is a need to provide a glaucoma drainage device (GDD) that avoids or at least ameliorates one or more of the disadvantages described above. The non-limiting exemplary embodiments of a GDD of the present disclosure satisfy such a need.